The impact of metabolic plasticity on winter energy use models

Understanding energetic consequences of climate change is critical to identifying organismal vulnerabilities, particularly for dormant organisms relying on finite energy budgets. Ecophysiological energy use models predict long-term energy use from metabolic rates, but we don't know the degree to which plasticity in metabolism impacts estimates. We quantified metabolic rate-temperature relationships of dormant willow leaf beetles (Chrysomela aeneicollis) monthly from February to May under constant and variable acclimation treatments. Metabolic rates increased as diapause progressed, and acclimation to variable conditions altered both metabolic intensity and the thermal sensitivity. However, incorporating these two types of metabolic plasticity into energy use models did not improve energy use estimates, validated by empirical measurements of energy stores. While metabolic rate temperature relationships are plastic during winter, the magnitude of inter-individual variability in energy stores overshadows the effects of incorporating plasticity into energy use models, highlighting the importance of within-population variation in energy reserves.